<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>边框</title>
    <style>
        .c1{
            width: 400px;
            height: 200px;
            /*border-top-style: solid;*/
            /*border-right-style: dashed;*/
            /*border-bottom-style: dotted;*/
            /*border-left-style: double;*/
            /*border-top-color: red;*/
            /*border-right-color: green;*/
            /*border-bottom-color: blue;*/
            /*border-left-color: purple;*/
            border-style: solid dashed dotted double;
            border-color: red green blue purple;
            border-width: 10px 20px 30px 40px;
        }
        .c2{
            width: 200px;
            height: 100px;
            border: solid red 100px;
            border-radius: 10px 20px 30px 40px;
        }
        .c3{
            width: 200px;
            height: 200px;
            border: solid red 1px;
            border-radius: 50%;
        }
    </style>
</head>
<body>
<div class="c1"></div>
<hr>
<div class="c2"></div>
<hr>
<div class="c3"></div>
</body>
</html>